Method of manufacturing windings for disc-type dc machine armatures



Oct. 20, 1970 R. J. KEOGH 3,534,469

METHOD OF MANUFACTURING WINDINGS FOR DISC-TYPE DC MACHINE ARMATURESOriginal Filed March 5, 1967 4 Sheets-Sheet l I I q 1' Ng I o 'l l I f if I INVENTOR. RA YMONO .r, KEOGH A T romve' Ys I not. 20, 1970 R.J:.YKEOGH Q 3,534,459

METHOD OF MANUFACTURING WINDINGS FOR DISC-TYPE DC MACHINE ARMATURES IOriginal Filed March 5', 1967 4- Sheets-Sheet 2 con. 6 \f y con. 7 #6INVENTOR.

/26 O o 0 RAYMOND .mrsoau ATTORNEYS Oct. 20, 1970 R. J. KEOGH 3,534,469

' METHOD OF MANUFACTURING WINDINGS FOR DISC-TYPE DC MACHINE ARMATURESOriginal Filed March 3, 1967 4 Sheets-Sheet 5 COIL )5 OCLZO, 1970Original Filed-Max ch 3, 1967 R. J. KEOGH 3,534,469 I METHOD OFMANUFACTURING WINDINGS FOR DISC'TYPE DC MACHINE ARMATURES 4 Sheets-SheetL pasmou I ssusms umr STYL US MOTOR only; 7 rig v.

' DISC Moron 57 DRIVE C ON TROL UNI T 'PROGRAM I-NVENTOR.

- P RAYMOND .z'rrsoau F IG. 4 g Q W A 1' TORNE Ys United States Patent3,534,469 METHOD OF MANUFACTURING WINDINGS FOR DISC-TYPE DC MACHINEARMATURES Raymond J. Keogh, Huntington, N.Y., assignor to PhotocircuitsCorporation, Glen Cove, N.Y., a corporation of New York Originalapplication Mar. 3, 1967, Ser. No. 620,306. Divided and this applicationOct. 3, 1968, Ser. No. 798,497

Int. Cl. H02k /00 US. Cl. 29-598 14 Claims ABSTRACT OF THE DISCLOSURE AWire wound motor armature constructed by forming successive groups ofsingle turn armature coils, the coils within each group being inregistry with one another, the

groups being indexed relative to one another, and all coils beinginterconnected in a wave configuration.

The apparatus for forming the winding including a rotating winding formand a wire dispensing stylus moving radially, the movements of the formand the stylus being coordinated to form the winding.

This application is a division of co-pending application Ser. No.620,306 filed Mar. 3, 1967 in the name of Raymond J. Keogh.

BACKGROUND OF INVENTION In the construction of electric motor armaturesit has been generally accepted that the coil span of the individualarmature coils must be either slightly greater, or slightly less thanthe distance between adjacent magnetic pole centers. If the coil span isslightly less, a retrogressive winding results, whereas, if the coilspan is slightly greater, a progressive winding results. By having thecoil span slightly different from the distance between magnetic polecenters there is a slight indexing of the winding with each successivearmature coil and, as a result, the coils each have the sameconfiguration and are uniformly distributed over the armature surface ina symmetrical fashion.

In conventional DC machines the armature is usually formed withmultiturn, preformed coils which are placed in coil slots of a laminatediron core. Since the winding must conform to the armature slotlocations, it is desirable to have a uniform indexing of the windingwith respect to each successive coil such that all coils have the sameshape and all slots contain the same number of conductors.

In recent years the low inertia, printed circuit type of motor has beendeveloped eliminating the iron and coil slots in the armature. Theprinted circuit motor usually includes a disc shaped armature in whichradially extending array of conductors are usually bonded to oppositesides of an insulating carrier. The conductor patterns for the armatureare formed either by chemical techniques, i.e. plating, or etching, orby mechanical stamping techniques. The restrictions upon the windingconfigurations in a printed circuit motor are even more severe than inthe case of a conventional motor. For example, a two layer printedcircuit armature must be formed with single turn coils, the winding mustbe retrogressive and each coil must index the winding so that all coilshave the same configuration.

The printed circuit motor has the advantages of high acceleration andsmooth torque, but, because of the single turn coils, can only operateat relatively low voltages.

In a co-pending application, Ser. No. 511,608 filed Dec. 6, 1965, in thename of Robert Page Burr, having a common assignee with thisapplication, an insulated wire wound type of motor is illustrated aswell as the methods for making the same. This armature can be formed byPatented Oct. 20, 1970 depositing insulated wire around positioning pinsby means of a wire dispensing stylus. Each successive coil, which can besingle or multiturn, indexes the winding slightly to obtain a uniformlyprogressive or retrogressive Winding distributed around the positioningpins. This type of armature if constructed with multiturn armature coilscan operate at higher voltages but is difficult to construct withautomatic machinery because it is necessary to constantly reverse thewinding direction while forming the multiturn coils.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to an improvedwinding technique for wire wound armatures which do not include slotsfor the armature coils as well as the apparatus for making the winding.

The armature is formed by depositing insulated wire, preferably aroundpositioning pins, following a pattern forming a plurality of single turncoils which are all in registry and thus, if the pattern is continued,successive armature loops would occupy approximately the same positions.Instead of indexing the winding with the formation of each successivearmature coil, the winding is indexed only after a predetermined numberof coils have been formed in registry with one another.

BRIEF DESCRIPTION OF THE DRAWINGS An illustrative embodiment of theinvention is set forth in the drawings which form part of thespecification and wherein:

FIG. 1 is a perspective assembly drawing of the motor;

FIG. 2 is a cross sectional view of the assembled motor;

FIGS. 3A-3D are a series of diagrams illustrating the armature windingsequence;

FIG. 4 is a schematic illustration of winding apparatus for forming thearmature.

ARMATURE CONSTRUCTION GENERALLY The rotating winding for disc typemachine includes a large number of radially extending insulated wiresegments distributed to form an annular array which will be adjacent thestationary magnetic pole faces in the completed machine. These radiallyextending segments are interconnected to form a continuous winding whichis substantially planar, or in other words, is in the form of arelatively thin disc. Successive radially extending segments of thewinding are displaced by a distance approximately equal to the distancebetween pole centers of the associated magnetic structure and areinterconnected so that current flowing in the winding will flow in onedirection across the south poles and in the opposite direction acrossthe north poles.

The radially extending segments are preferably arranged to minimize thecrossing of conductors to thereby minimize the thickness of the armaturedisc within the magnetic air gap. The thinnest possible windingconfiguration would occur where all radially extending segments aresubstantially radial. However, when automatic winding techniques areemployed, it is often preferable to have the radially extending segmentssomewhat skewed.

The portions of the winding which interconnect the radially extendingsegments and which lie outside the annular air gap area have a thicknessat least twice the diameter of the conductors. As the crossover areas ofthe armature winding are decreased in width, for example, to reduce thediameter of the armature, additional stacking of the conductors occursand hence the thickness of the armature winding in these areasincreases. However, the crossover connections, by definition, are notwithin the working air gap of the machine and, therefore, this increasedthickness is not detrimental to the performance of the machine.

The winding is formed in a continuous fashion utilizing insulated wireand, since the conductors are insulated, it is possible to crossconductors as desired. The copper distribution can be controlled toachieve a low copper density in the area of the air gap and a highercopper density in the thicker crossover areas outside the air gap. Thiscontrol over the relative copper density permits the designer tooptimize performance for a particular size armature disc.

An armature turn is the portion of the winding including two successiveradially extending segments. When the armature is constructed inaccordance wtih this invention the armature coils are each single turncoils, and, therefore, each armature coil likewise includes twosuccessive radially extending segments. An armature loop is a portion ofthe winding which spans approximately 360 degrees of the armature. Thus,with an eight pole machine an armature loop includes four successivearmature coils whereas with a 12 pole machine an armature loop includessix successive armature coils.

If the armature coils comprising a loop are in registry, the armatureloop spans exactly 360 degrees and if successive armature loops are inregistry with the first, the successive armature loops occupyessentially the same positions. For the purposes of this invention,armature coils are defined as being in registry where they are part ofan armature loop which, if completed, would be in registry with theprior armature loop or portions thereof. Indexing of the winding occurswhen successive armature loops or portions thereof lie in positionsadjacent prior armature loops.

FIGS. 3A-3D illustrate the step by step formation of an armature windingfor an eight pole machine including 117 armature coils and ninecommutator segments. The winding is formed about a jig or die includinginner and outer rows of positioning pins, each such row including 27pins. The inner pins are designated 1a-27a and the outer pins arelikewise designated 1b-27b. The tabs for connection to the commutatorsegments are designated A-L in the order of connection.

Since the armature is for an eight pole machine, each armature loopincludes four armature coils. Since there are 27 positioning pins eacharmature coil spans approximately eight positioning pins. Since thereare 117 coils and nine commutator segments, every thirteenth coil isconnected to the commutator.

The armature winding commences by attaching the insulated wire to one ofthe commutator connection tabs designated as tab A. Tab A is in radialalignment with the first set of positioning pins 1a and 1b. The windingthen passes outside positioning pins 2a 3b, 4b and 5b in succession. Thefirst armature coil is then completed by passing the wide inside pin 7a.

Next, the second armature coil is formed by passing the wire inside pin8a, outside pins b-12b, and inside pin 14a. The winding continues bythen forming the third and fourth armature coils by passing inside pina, outside pins 17b-19b, inside pins 21a and 22a, outside pins 24b-26band inside pin 1a. At this point the first armature loop spanning 360degrees is completed as is illustrated in FIG. 3A.

Thesecond armature loop is in registry with the first armature loop andis formed following the same sequence around the positioning pins asshown in FIG. 3B. The third armature loop is also in registry as well asthe first coil of the fourth armature loop. The winding as it appearsafter formation of three and one-quarter armature loops (13 coils) isshown in FIG. 30. Each of the 13 coils in the first group are inregistry with one another and follow the same pattern about thepositioning pins.

A commutator pull out is formed following the first group of 13 coils bypassing the winding around tab B. At this point the winding is alsoindexed so that the second group of thirteen coils will lie in positionsadjacent the first group.

The winding progresses by passing outside pin 8a, outside pins 9b-11b,inside pins and 14a, outside pins 1617-1817, inside pins 20a and 21a,outside pins 23b25b and iiside pin 27a. The winding as it then appearsafter completion of four armature loops (l6 coils), including threecoils of the second group, is shown in FIG. 3D. Coils 14-16 of thesecond group are indexed relative to coils 1-13 of the first group.

The winding sequence for the entire 117 coil armature is set fourth inTable I.

TAB LE I Start of coil Outer pins End of coil '3 1033 11 15 17-19 21 2224-26 1 i 10 11 15 17-19 21 22 24-26 1 l 10 i; 11 15 17-19 21 22 24-26 11 3-5 6, B

First Pu11outfi1'st index point Loop 4. B, 3 9-11 13 14 16-18 20 2123-25 27 l 9 1? 1; 14 16-18 20 LOOP 21 23-25 27 Second Pu11outseeondindex point Loop 7.

13 15-17 19 LOOP 20 22-24 26 27 2-4 6 7 9-11 13 13 15-17 18, D Loop 10.Third Pullouttl1ird index point D, 20 21-23 25 E 8 13 13 13 15-17 19M01) 19 21-23 25 2 16 13 15-17 19 LOOP 19 21-23 25 Fourth Pullout-fourthindex point 5 55 12 14-16 is 14 56 19 21-23 25 6 3 5 59--- 12 14-16 1360..- 19 21-23 25 61. 25 2g-2 4 62. 5 -9 11 63. 12 14-16 16 16 64. 1921-23 25 65. 25 27-2 5,11

Fifth Pulloutfifth index point Loop 17. 66 1 5 6-8 10 67 11 13-15 17 6813 20-22 24 6 25 63 5 TABLE I Coil Start of coil Outer pins End of coilSixth pullout-sixth index point Loop 20.

G, 11 12-14 16 17 19-21 23 e 21 s 4 10 12-14 16 LOOP 17 10-21 23 24 26-13 4 6-8 10 10 12-14 15, H

Loop 23. Seventh pulloutseventh index point Eight pull0ut-eigl1t indexpoint 1,23 24-26 1 2 4-6 2 9 1 -13 16 18-20 22 22 24-26 1 2 kg 9 11-1 1618-20 22 22 24 2 i 2 9 1143 Loop 29. 16 18-20 22 v 22 24-26 27, AClosing coil.

ARMATURE DESIGN CONSIDERATIONS In designing an armature certain factorsmust be known at the outset. These factors are, for example:

(1) The outside diameter of the armature; (2) The number of pole pairsin the magnetic structure; (3) The flux level which will be produced bythe magpairs, :1) equals flux per pole in Maxwells, and N equals thenumber of conductor pairs or armature turns.

Substituting the aforementioned factors into Formula 1 provides thefollowing:

it 0.022 volt/rad/sec. (3)

Thus, it is determined that approximately 97 conductor pairs (armatureturns) provides 0x022 volt/rad/sec. which in turn is equal toapproximately 2.2 volts per 10010 rpm.

Formula 1 assumes an armature coil shape which is carefully selected toconform to the shape of the magnets forming the stator poles. In theinterest of simplicity and winding speed a simplified configuration hasbeen adopted as shown in FIGS. 3A-3D which is approximately 80%efiicient. Thus, to obtain the desired characteristics the number ofarmature turns is increased by a factor of 1.2, and hence, approximately116 armature turns are required.

For simplicity the number of commutator segments should be a sub-mutipleof the number of armature turns. If dead coils are to be avoided, thenumber of commutator segments must be odd if the number of pole pairs iseven and vice versa. Furthermore, the commutator connection pointsshould occur at regularly spaced intervals throughout the armaturespaced by a number of complete armature loops plus or minus one armatureturn. Thus, the coil spacing between commutator connection points can beexpressed:

wherein Y equals the number of armature turns between commutatorconnection points, p equals the pairs of poles (also number of armatureturns per armature loop), n is an integer multiplier and the or sign ischosen to yield a progressive or retrogressive winding, as desired.

Tabe II indicates the number of conductors required in the armature foran eight pole machine having various combinations or of commutatorsegments and distances between commutator connection points inaccordance with the relationship:

netic structure; 45 n (p) +1 -(5) TABLE II 1% loop/ 2% loop/ 3% loop 4%loop/ 5% loop/ 6% loop pullout (5 pullout (9 pullout (13 pullout (17pullout (21 pullout (25 No. of commutator conductor conductor conductorconductor conductor conductor segments pairs) pairs) pairs) pairs)pairs) pairs) (4) The desired voltage constant for the armature, thatis, the voltage generated by the armature per 1000 rpm;

(5) The winding resistance.

These factors are interrelated, and, particularly factors 3, 4 and 5must be compatible if a reasonable armature is to result.

For the armature shown in FIGS. 3A-3D these factors are an outsidearmature diameter of 3.6 inches, four pole pairs (eight poles), a fluxwheel of 5.3 kilogauss as can be obtained -with Alnico permanentmagnets, a voltage constant of 2.2 volts per 1000 rpm, and a windingresistance of two ohms end to end.

The number of armature conductors can be determined by the followingformula:

From Table II it can be seen that an armature having thirteen commutatorsegments and commutator connection points spaced by 2% armature loops (9armature turns or conductors pairs) would have a total of 117 armatureturns; an armature with nine commutator segments and a spacing betweencommutator connection points of 3% loops (13 conductor pairs or armatureturns) would also have a total of 117 armature turns; and an armaturewith seven commutator segments and a spacing between commutatorconnection points of 4% armature loops (17 conductor pairs or armatureturns) would include a total of 119 armature turns. Any of these threecombinations could be used for the armature under consideration whereinthe desired number of armature turns is approximately 116.

A similar table could be developed for an eight pole machine with thespacing between commutator connection points according to the formula:

In this arrangement the commutator connection points would occur at A,1%, 2%, etc., armature loops. From this additional table othercombinations can be found which could be used in the design of anarmature having approximately 116 armature coils.

For the armature shown in FIGS. 3A-3D the combination of nine commutatorsegments and commutator connection points separated by 3%. armatureloops (13 armature turns) has been selected which provides an armaturewith a total of 117 armature turns, this selection being sufficientlyclosed to the desired number of armature turns.

The criteria for the location of the indexing points is the same as thatfor the location of commutator connection points, and hence isrepresented by Formula 4. For convenience, the indexing points arenormally selected to coincide with the commutator connection pointssince it is possible to make both the commutator connection and to indexthe winding as part of the same step in the winding sequence. However,the commutator connection points and the indexing points need notcoincide nor need the coil spacing between commutator connection pointsbe the same as that between successive indexing points.

The number of positioning pins used in forming the armature must be amultiple of both the number of com mutator segments and the number ofindexing points. In the armature under consideration, the number ofcommutator segments has been selected as nine and the number of indexingpoints is also nine. Accordingly, the armature can be constructed usinga number of positioning pins which is a multiple of nine. A betterwinding distribution occurs as the number of positioning pins increases,but as the number of positioning pins increases, the complexity of thearmature winding apparatus also increases. Furthermore, a practicallimit is reached when the spacing between positioning pins of the innerrow approaches ten pins per inch. For the winding under consideration amultiplier of three has been selected and hence there are 27 positioningpins.

The wire size is determined by measuring the approximate length of anarmature turn, multipling this length by the number of turns in thearmature to obtain the total armature length, and by then consulting awire table to select a Wire size which provides the desired armatureresistance. From a standard copper wire table number 28 gauge wire isfound satisfactory for the armature under consideration having aresistance of two ohms end to end.

In many cases it is desirable to construct the armature usingmultistrand insulated wire as this tends to provide a thinner moreevenly distributed winding. Such an armature can be formed by dispensingmultistrand wire as the armature'is formed. The same armature can alsobe made by repeating the entire winding sequence several times with asingle strand of wire. A pair of 31 gauge copper wires would provideessentially the same electrical characteristics for the winding underconsideration.

The winding technique in accordance with the invention is quite flexibleand is highly desirable since a large number of different armatures canbe made utilizing the same automatic winding apparatus and can often bemade using the same winding forms, i.e. winding forms with the samenumber of positioning pins.

MOTOR ASSEMBLY An insulated wire wound disc type motor in accordancewith one embodiment of this invention is shown in FIGS. 1 and 2. Themotor is enclosed within a twopart housing 1 including a base plate 2. Astationary permanent magnet structure 3, brush holders 4 and one of thebearings 5 are mounted on the base plate. The other bearing 6 is mountedwithin a central opening in the cup-shaped member 7 forming the otherpart of the motor housing, member 7 being secured to the base plate atits periphery by means of screws 8.

The motor shaft 9 is journaled in bearings 5 and 6, and includes anintermediate section 10 of increased diameter. The increased diametersection is positioned between the bearings and prevents axial movementof the shaft. The motor armature 14 is mounted on shaft 9 by means of aflanged hub 11 rigidly secured to the shaft and an associated flangednut 12 which cooperates with the external threads on the shank portionof the hub. The dielectric disc 17 forming part of armature 14 isrigidly secured between the flanges of nut 12 and hub 11.

The armature winding constructed as described in relation to FIGS. 3A-3Dis supported on a dielectric disc 17 shown adjacent the winding forillustration purposes. The commutator segments 16 are centrally locatedwith respect to the winding and are secured to dielectric disc 17. Theflange of hub 11 provides structural backing for the commutator toprevent distortion of the armature disc due to the force exerted againstthe commutator by the brushes.

The motor illustrated in FIGS. 1 and 2 is an eight pole motor andtherefore the permanent magnet structure 3 is divided into eightsegments which provide the necessary pole faces. The permanent magnetstructure is a unitary ring-shaped member provided with slots 20 whichdefine individual bosses that form an annular array of the pole faceslying in a plane perpendicular to the axis of rotation. The magneticstructure is a cast or sintered unit fashioned from anickel-aluminum-cobalt alloy such as Alnico. The structure is magnetizedto provide pole faces of alternating magnetic polarities. A ring 18 ofsoft iron is secured to the rear of the housing by screws 19 to completethe magnetic path between adjacent pole faces. The space between ring 18and the pole face surfaces is the working air gap of the machine andmust be sufficient to accommodate the armature and provide a workingclearance.

A few turns of heavy, insulated wire, referred to as a charging winding,are placed around the individual pole pieces prior to final assembly.Charging winding 39 passes outside one pole piece 22, through a slot 20,and then inside the next pole piece 21, etc., twice around the unit.This winding in effect surrounds one pole piece in a clockwisedirection, and surrounds the adjacent pole piece in the counterclockwisedirection and, therefore, current flow through the charging windingtends to produce poles of alternating magnetic polarity. After finalassembly the charging winding is energized to magnetize the permanentmagnets.

The radially extending segments of the armature winding lie within theworking air gap adjacent the pole faces. The thickness of this portionof the armature winding within the air gap is maintained at a minimum.The thicker portions of the winding which include the crossoverconnections are located outside the air gap.

Brush holders 4 each include an insulated sleeve having a cylindricalbody portion 25, the end of which extends through suitable openings 27.The brushes 29 are rectangular in cross section and extend from thebrush holders through suitably dimensioned rectangular openings 28. Theend of the brush holder opposite the rectangular opening is internallythreaded and adapted to receive a flat head screw 32. When the screw isinserted, pressure is applied to the brush via a spring 30 and smallpressure plate 31, so that the brush is maintained in engagement withcommutator segments 16. The number of brushes and the placement relativeto the pole faces varies in accordance with the armature winding andcurrent carrying requirements.

WINDING APPARATUS The armature can be constructed by distributinginsulated wire upon a planar surface in continuous fashion. This isaccomplished using a winding form 40 as shown in FIG. 4 havingappropriately positioned pins 41 extending upwardly from the planarsurface so that the sulated wires forming the armature can be woundaround the pins. The pins are located in two concentric rows. Thepositioning pins in the inner row are designated 1a- 27a, and thepositioning pins in the outer row are designated 1b-27b, therebycorresponding to those shown in FIGS. 3A-3D.

The insulated wire can be distributed directly upon the planar surfaceof the winding form, or upon a disc blank 44 as shown. Holes are drilledor punched into the disc blank corresponding to the positions of thepositioning pins and, hence, when the blank is dropped into position asshown in FIG. 4, the pins extend upwardly through the blank. The discblank includes the commutator segments 45 secured to the discsurrounding a central opening which will accommodate the motor shaft andhub structure. Each commutator segment includes an upwardly extendingtab, these tabs being used to position the commutator pullout loops ofthe winding.

Winding form 40 is coupled to a motor '50 which rotates the winding formin the clockwise direction. A position sensing unit 51 is coupled to themotor shaft and provides electrical signals indicating the instantaneousposition of the winding form.

The insulated wire is dispersed by a stylus 52 mechanically coupled'to alead screw 5-3 which moves the stylus radially relative to the windingform. The movement of the stylus is controlled by a bidirectional,variable speed motor 54- coupled to the lead screw.

The operation of motors 50 and '54 is controlled from a control unit 56,respectively, via a disc motor drive 57 and a stylus motor drive 58. Thecontrol unit operates in accordance with a preselected program tocoordinate the movements of the winding form and the stylus to form thedesired winding configuration. The entire armature winding is formedwhile the Winding form rotates in a single direction, and hence, sinceit is not necessary to periodically reverse the direction, relativelyhigh winding speeds are readily attainable. As the winding form rotates,position sensing unit 51 provides signals indicating the position of thewinding form, and these signals are compared with the program to controlthe corresponding radial movements of the stylus.

The winding forms and control programs are preferably interchangeable sothat the same winding apparatus can form armatures of various sizes andvarious contfigurations.

After the insulated wire has been distributed to form the winding it isnecessary to give it structural integrity to deflect the armature winding in an axial direction and therefore the armature need only havesuflicient rigidity to maintain clearance with respect to the stationarystructure and to transmit torque between the winding and the motorshaft. Structural integrity is achieved by one of the followingprocesses or combinations thereof:

(1) The winding is formed upon the surface of a thermoplastic disc blankas shown in FIG. 4, and when completed, heat and pressure are applied topress the winding into the disc blank. The winding, particularly in theannular air gap area, is embedded in the disc and has a thickness nogreater than the insulated Wire. The same result can be achieved byforming the winding without the disc blank and thereafter pressing thethermoplastic disc down upon the preformed winding.

(2) The winding can be laminated between a pair of thermoplastic discs.The winding is preformed and thereafter placed between the laminatingdiscs, or can be wound upon one of the disc blanks as shown in FIG. 4.Preferably, the structure is compressed in the air gap area to manimizethe thickness.

(3) The winding can be formed directly upon the winding form without adisc blank and thereafter coated, as by spraying, dipping or the like,with a suitable dielectric medium to provide structural integrity.

(4) The winding can be formed directly upon the winding form without adisc blank and thereafter spotted with an adhesive material to bond theinsulated wires at points where the conductors cross.

(5) The winding can be formed with a heavy gauge wire which by itselfposseses sufficient structural integrity.

SPECIFIC ARMATURE DESIGNS There are a substantial number of possiblearmature designs within the scope of the invention. Several specificexamples, in addition to that previously described, are as follows:

EXAMPLE NO. 1

The positions of the commutator pullouts need not coincide with thepositions of the index points. A winding sequence for such an armaturecould be:

Start at a commutator connection; Wind one full armature loop; Indexahead two pins;

Wind 1% armature loops;

Form a commutator pullout; Repeat.

The parameters and predicted operating characteristics for such anarmature are as follow:

Number of poles8 Number of commutator segments27 Number of armatureconductors-594 Number of armature turns297 Number of positioning pinsper row-81 Number of armature turns between indexing points-11 Number ofarmature turns between commutator pulloutsl1 Type of winding-ProgressiveWire size-#30 A.W.G.

Outside diameter of armature--3.6 inches Inside diameter of armature-2.0inches Armature resistance (including brushes)l.9 ohms Field flux5kilogauss Voltage constant, K 5.5 v./k.p.m.

Torque constant K 7.4 in.-oz./amp

Dumping constant, K -0.l8 in.-oz./k.p.m.

EXAMPLE NO. 2

The indexing points can be separated by less than a complete armatureloop as indicated, for example, by Formula 6 when nequals one. For amachine including four pole pairs the armature winding sequence wouldbe:

start at a commutator connection; 'Wind A of an armature loop; indexbackward (retrogressive); form a commutator pullout; repeat.

The parameters and predicted operating characteristics for such anarmature are as follows:

Number of poles8 Number of commutator segments--35 Number ofconductors-210 Number of tums--l05 Number of pins in form (outer row)lO5Number of turns between indexing points--3 Number of turns betweencommutator segments3 Type of windingRetrogressive Wire size#24 A.W.G.

Outside diameter of armature6.6 inches Inside diameter of armature-3.5inches Armature resistance (excluding brushes)0.3 ohm Field flux-18kilogauss Voltage constant, K 5.5 v./k.p.m.

Torque constant K -7.4 in.-oz./ amp Damping constant, K 1.21in.-oz./k.p.m.

EXAMPLE NO. 3

The number of positioning pins in the winding form can be odd or even.The winding sequence for an armature formed with an odd number ofpositioning pins having indexing points separated by an armature loopplus a fraction and having indexing points non-coincident with thecommutator connection points could be:

start at a commutator connection;

wind one full armature loop;

index backward (retrogressive) one positioning pin; wind armature loop;

form a commutator pullout;

repeat.

The parameters and predicted operating characteristics in such anarmature are as follows:

Number Number Number Number Number Number EXAMPLE NO. 4

An armature having characteristics almost identical to Example No. 3 canbe formed using an even number of positioning pins. The winding sequencefor such an armature being progressive and having coincident commutatorpullouts and indexing points could be:

start at a commutator connection; wind 1% armature loops;

form a commutator pullout; repeat.

The parameters and predicted operating characteristics are as follows:

Number of poles8 Number of commutator segments-11 Number ofconductors-154 Number of turns-77 Number of pins in form (outer row)-44Number of turns between indexing points7 Number of turns betweencommutator segments7 Type of windingProgressive Wire sizeDoublestrand(bifilar)-#28 A.W.G. Outside diameter of armature3.6 inches Insidediameter of armature2.0 inches Armature resistance (excludingbrushes)-0.255 ohm Field flux5.5 kilogauss Voltage constant, K 1.44v./k.p.m.

' Torque constant, k 1.94 in.-oz./amp

Damping constant, K 0.181 in,-oz./k.p.m.

EXAMPLE NO.

The indexing points can be separated by more than a plurality ofarmature loops. The winding sequence for an armature having indexingpoints separated by 3% armature loops could be:

start at a commutator connection; wind 3% armature loops;

form a commutator pullout;

index backward one positioning pin; repeat.

The parameters and predicted operating characteristics for such anarmature are as follows: Number of poles8 of commutator segments17 ofconductors442 of turns-221 of pins in form (outer row)--68 Number ofturns between indexing points13 Number of turns betweencommutatorsegments13 Type of winding-Retrogressive Wire size doublestrand (bifilar)-#28 A.W.G. Outside diameter of arfnature3.6 inchesInside diameter of armature2.0 inches Armature resistance (excludingbrushes)0.74 ohm Field flux5 .5 kilogauss Voltage constant, li -4.14v./k.p.m.

Torque constant, K 5.60 in.-oz./ amp Damping constant, K 0.52in.-oz./k.p.m.

EXAMPLE NO. 6-

The distance between commutator connection points can be different fromthe distance between indexing points. A Winding sequence for such anarmature could be:

Number Number Number Number start at a commutator connection;

wind 2% armature loops;

index ahead one positioning pin;

wind one armature loop;

form commutator pullout;

winding 1% armature loops (total of 4 /2 loops from beginning;

index ahead one positioning pin;

wind two armature loops;

form commutator pullout;

continue sequence, indexing after every 2% armature loops, and forming acommutator pullout after every 3% armature loops.

The parameters and predicted operating characteristics for such anarmature are as follows:

Number of poles-8 Number of commutator segments9 Number of armatureconductors234 Number of armature turns117 Number of positioning pins perrow27 Number of armature turns between indexing points-9 Number ofarmature turns between commutator connection points-13 Type ofwinding-Retrogressive Wire size-28 A.W.G.

Outside diameter of armature3.6 inches Inside diameter of armature2inches Armature resistance (including brushes)OzS ohms Field flux-5 .3kilogauss Voltage constant K 2.2 v./k.p.m.

Torque constant K 2.9 in.-oz./amp

Dumping constant K 1 in./k.p.m.

While several specific embodiments have been described in detail itshould be obvious that there are numerous other embodiments within thescope of the invention. The invention is applicable to cylindricalarmature as well as disc shaped armatures, and is more particularlydefined in the appended claims.

What is claimed is:

1. A method of constructing an armature for an electrical machine havinga multipole magnetic structure, including the steps of distributinginsulated Wire on to a substantially planar surface and in a continuousfashion by means of a wire dispensing device automatically controlled tofollow a predetermined path relative to the surface to form successivegroups of single turn armature coils,

all coils within a group being in registry with one another, each coilincluding a pair of winding segments spaced approximately in accordancewith the distance between adjacent pole centers of the associatedmagnetic structure, and

13 said coils being interconnected in a wave configuration; indexingafter formation of each group of coils so that one group of coils liesin coil positions adjacent those of a prior group of coils; and Icontinuing the winding until the end of a group of coils substantiallycoincides with the starting point for the winding. I

2. The method according to claim 1 wherein each group includes the samenumber t coils.

3. The method according to claim 1 wherein said indexing is progressive.

4. The method according to claim 1 wherein said indexing isretrogres'sive.

5. The method according to claim 1 wherein said winding is formed bydistributing the insulated wire upon a disc form, and wherein thecompleted armature winding is embedded in said disc form. c

6. The method according to claim 1 wherein said winding is formed bydistributing multistrand insulated w1re.

7. A method of constructing an armature for an electrical machine havinga multipole magnetic structure, including the steps of distributinginsulated wire on to a substantially planar surface and in a continuousfashion by means of a wire dispensing device automatically controlled tofollow a predetermined path relative to the surface to form successivegroups of single turn armature coils,

each of said groups including the same number of coils, said number ofcoils being in accordance with the relation wherein n is an integer andp is the number of pole pairs in the magnetic structure,

all coils within a group being in registry with one another, and

each coil including a pair of winding segments spaced approximately inaccordance with the distance between adjacent pole centers of theassociated magnetic structure,

indexing after formation of each group of coils so that one group ofcoils lies in coil positions adjacent those of a prior group of coils;and

continuing the winding until the end of a group of coils substantiallycoincides with the starting point for the winding.

8. The method according to claim 7 wherein connections are made tocommutator segments at regularly spaced intervals throughout saidwinding.

9. The method according to claim 8 wherein said connections are madewhile indexing between successive groups of coils.

10. A method of constructing an armature for an electrical machinehaving a multipole magnetic structure, including the steps ofdistributing insulated wire on to a substantially planar surface and ina continuous fashion by means of a wire dispensing device automaticallycontrolled to follow a predetermined path relative to the surface toform successive groups of single turn armature coils,

all coil's within a group being in registry with one another, each coilincluding a pair of winding segments spaced approximately in accordancewith the distance between adjacent pole centers of the associatedmagnetic structure, and said coils being interconnected in a waveconfigura tion; indexing after formation of each group of coils so thatone group of coils lies in coil positions adjacent those of a priorgroup of coils; and forming commutator connection points at regularlyspaced intervals throughout the winding, the number of coils betweencommutator connection points being where n is an integer and p is thenumber of pole pairs in the magnetic structure; and

continuing the winding until the end of a group of coils substantiallycoincides with the starting point for the winding.

'11. The method according to claim 10 wherein each of said groupsincludes the same number of coils, said number of coils being inaccordance with the relation 11' (p) :1 wherein vn is an integer and pis the number of pole pairs in the magnetic structure.

12. The method according to claim 11 wherein the distance betweensuccessive indexing points is the same as the distance betweensuccessive commutator connection points.

13. The method according to claim 11 wherein said indexing pointscoincide with said commutator connection points.

14. The method according to claim 10 wherein said winding is continuedbeyond said starting point and the end of said winding is connected tothe beginning after passing said starting point a plurality of times,said winding being connected at each of said commutator connectionpoints at least two times.

References Cited UNITED STATES PATENTS 295,534 3/1884 Prick 310-268459,610 9/ 1891 Desroziers 310-268 514,907 2/ 1894 Brush- 310-268 JOHNF. CAMPBELL, Primary Examiner C. E. HALL, Assistant Examiner U.S. Cl.X.R.

